We posted a video at the end of 2024 from a few years ago where we were looking at running our servers from solar. Here is the video:
We have a server farm here which has a full rack of servers and data storage. we have other non racked servers but the power on these are pretty low so that’s not really the big issue.
With servers being the “home lab” or the small business to large data centers, can solar really power the whole thing?
Solar wont power anything by itself as surely as day follows night, and for that very reason. So what you have to consider is the actual power used by the server and having the same redundant power as you would for a grid fail. But also the grid as well.
In 2023, data centers across the globe consumed 7.4 GW of power, a 55% increase from 2022
Lets say you have a kitted HP server which is going to be around 400W
So the math here is easy, 400w x 24h will give you 9.6kWh per day (24hours)
Lets then make 9.6kwh from 4 hours of sun is 2.4kw per hour or 3.2kw of solar.
using 535w panels, you can see how the system will not use power generally over that of a single panel, but because the sun is not 24hours we need to charge a battery. if the sun was 12 hours and night 12 hours, then you would need 2 time the solar. but that is not always the day and night ratio.
On the other hand, if you have a micro server, then the power consumption is much lower and therefore the demand for solar is a lot less, about 1.2kwh a day. the problem here is that if you have an inverter you have to manage the power draw from running this which can be as much as 65w, thus doubling the power draw. The key here would be to to have DC to DC, and remove the inverter all together.
DC Direct
Typically servers have two voltages, 12 and 5.
400w @ 12v is 33.33 amps and for the most part you can get that amps from solar panels.
a 420w solar panel will be around 37v and 14 amps. If we power factor this we would have about 40 amps, which is enough to power a server. but that is at peak power. so the likelihood of running a 400w server from a 420w solar panel is actually slim. this would be due to the fact they never really run at peak power for more than a few hours of the day. I believe the panel is more like 320w peak in NOCT. Then you have to consider clouds which will drop the power considerably, so you would need a buffer (battery)
and to have over provisioned the solar. a 2s2p configuration would work better, as you would raise the voltage to rely on ohms law, and also have double the peak current. This does have a downfall in that hardware costs tend to grow with current.~
74v/ 12v= 6.166
14a x 2 =28
28a x 6.166 = 172 amps
5a x 6.166 is 30.83 amps
I used a 5 amp power rate, as that is 2.5amps per panel and fairly low light conditions. it is just under our required 33.33 amps for 400w and you can apply this to other sets ups and power use. but remember that you would still have a power range between 30 and 172 amps from the solar over the year!
for every hour of peak power would would get 5 hours of server run time.
You could run a 12v 140ah battery to power the 50w server.
KEY NOTES:
Running a server from solar, requires the total power in 24hours.
The total of solar power in one day, must be greater or equal to the power required in total.
You must compensate for losses and changing sun hours over the year.
Converting DC to DC to AC to DC will have losses
inverters will use power too.
Solar can be up and down in power, therefore unstable without a buffer.
Servers should be low power.
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